This invention relates to the generation of audio signals during play of a software carrier, and more particularly to a technique by which numerous audio signals may be recorded on separate audio tracks of the same carrier in a manner which permits the selective processing and combining of such signals.
The invention can be best appreciated by considering an application which it is believed will be among the most important uses of the invention. An optical disk has recorded on it dozens of audio tracks, each of which represents play of an individual musical instrument, play of a group of musical instruments, or a vocal rendition. The user may select which of the audio signals should be combined to generate a composite xe2x80x9cresult.xe2x80x9d The level (gain) of each track in the composite output signal, developed in an audio processor decoder, can be adjusted by the user so that particular instruments can be emphasized or eliminated. Thus a user who wants to practice as a soloist with a full orchestra could, for example, eliminate the xe2x80x9cpianoxe2x80x9d track and play along with the rest of the orchestral mix. (An alternative approach is to provide a track with a full orchestral mix, and to use a negative gain for the piano trackxe2x80x94in effect, the piano play would be deleted from the full orchestral recording.) Or the user might single out the piano track by itself, and play along with it.
Certainly, the idea of providing xe2x80x9cmusic minus onexe2x80x9d prerecorded media, in which one instrument is left out of the mix, is not new. But providing a recording with one instrument left out does not approach the flexibility contemplated by the present invention, in which every one of dozens of audio tracks can be controlled (mixed or deleted) by the user. It is contemplated that use of the present invention could extend the karaoke form of entertainment significantly. For example, a newly arrived player of an instrument could join a group of musicians already rehearsing simply by deleting another track from an overall orchestral recording.
The invention is described in the context of an optical disk and the digital storage of audio signals. It is to be understood, however, that the invention is not limited to a particular medium, and it is applicable to tape carriers and all digital storage media, not just the optical disks of the illustrative embodiment of the invention. Nor is the term xe2x80x9caudio signalxe2x80x9d restricted to music. For example, the invention is applicable to a carrier containing different types of sound effects recorded in respective tracks, with the user thus being able to mix them selectively depending on the particular application at hand. Another example would be the provision of alternative PG-rated soundtrack segments, to accompany a motion picture which is R-rated only because of explicit language in its soundtrack; by switching between the soundtracks, a PG-rated version of the motion picture may be played.
In the illustrative embodiment of the invention, there may be up to 63 tracks with different audio signals that can be mixed or combined with one another. (The word xe2x80x9ccombinedxe2x80x9d is used in a broad sensexe2x80x94it includes subtracting one signal from another, in effect deleting one signal from another more inclusive signal.) A design question that must be confronted is how the user is told which signal is recorded in each track. Another issue is how the user informs the player of which tracks should be combined. And however the user is informed of what is on the disk, since music is in a sense universal and not limited to a particular spoken language, it would be very convenient to communicate with the user in a language which he understands without requiring the production of different disks for different languages when language may be irrelevant to the music itself.
In accordance with the invention, the lead-in section of the software carrier includes textual data which defines the audio contents of the individual tracks. The textual data is in multiple languages. There is a code recorded for each available language, and each player represents a default languagexe2x80x94for players sold in France, for example, French would be the default language. The player software compares the player default language with those available on the disk. If there is a match, then only the French textual data is used to form the menu displays. On the other hand, if the default language is not represented on the disk, then the user is provided with a list of the represented languages so that he may select a different default language.
The player software includes provision for displaying the track information, and allowing the user to select which tracks should be played or not, and their respective levels (gains). The menu displays and the mechanisms for making selections, controlling levels, etc. can be of standard types. Menu displays and the inputting of selections are well known to users of personal computers and consumer electronic products. (For example, conventional videocassette recorders are controlled by menu displays and user selections.)
The use of predetermined software for controlling menu displays and user inputs limits flexibilityxe2x80x94the only variability is in the track definitions which, of course, depend on the audio content of the particular disk being played. But it is possible that in some cases non-standard menu choices will be desired. For example, the standard software which is contemplated processes the audio signals in a synchronized fashion. But suppose that a software publisher, for a particular disk, desires to allow the user to alter the phase relationships among the various tracks, e.g., by delaying tracks relative to each other in order to achieve non-standard reverberation effects. This would require not only different types of menu choices, but it would require changes in the basic processing software (e.g., delaying the processing of data in one track relative to another). Even this, however, is accommodated for in the invention. It is commonplace today to distribute software on optical disks. All that is necessary is to include on the optical disk of the invention software which is loaded into the player when the disk is first read, which software modifies or replaces the standard software for processing the audio track data. In this way, total flexibility can be achieved.-IN
The invention is disclosed in the context of an overall system which offers numerous advantageous features. The entire system is described although the appended claims are directed to specific features. The overall list of features which are of particular interest in the description below include:
Video standard and territorial lock out.
Play in multiple aspect ratios.
Play of multiple versions, e.g., PG-rated and R-rated, of the same-motion picture from the same disk, with selective automatic parental disablement of R-rated play.
Encrypted authorization codes that prevent unauthorized publishers from producing playable disks.
Provision of multiple-language audio tracks and multiple-language subtitle tracks on a single disk, with the user specifying the language of choice.
Provision of multiple xe2x80x9cotherxe2x80x9d audio tracks, e.g., each containing some component of orchestral music, with the user choosing the desired mix.
Variable rate encoding of data blocks, and efficient use of bit capacity with track switching and/or mixing, to allow all of the above capabilities on a single carrier.